Question

sin22× cos78 + sin78 ×cos22
​

Answer 1

Answer:

The required answer is sin $22$° cos $78$° + sin $78$° cos $22$° =$1$

Step-by-step explanation:

Given: The expression is sin $22$° cos $78$° + sin $78$° cos $22$°

To find : Find the expression's value.

Using Formula : sin ($A$ + $B$) = sin $A$ cos $B$ + cos $A$ sin $B$

Note the expression that is given.

The expression provided is

sin $22$° cos $78$° + sin $78$° cos $22$°

There is a trigonometric formula that we are aware of.

sin ($A$ + $B$) = sin $A$ cos $B$ + cos $A$ sin $B$

So, we obtain

sin $22$° cos $78$° + sin $78$° cos $22$°

= sin $22$° cos $78$° + cos $22$° sin $78$°

= sin ($22$° + $78$°)

= sin $90$°

= $1$

Hence, the answer is $1$

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